Climate in Contra Costa County, California

Contra Costa County, California gets 21 inches of rain, on average, per year. The US average is 38 inches of rain per year.

Contra Costa County averages 0 inches of snow per year. The US average is 28 inches of snow per year.

On average, there are 260 sunny days per year in Contra Costa County. The US average is 205 sunny days.

Contra Costa County gets some kind of precipitation, on average, 62 days per year. Precipitation is rain, snow, sleet, or hail that falls to the ground. In order for precipitation to be counted you have to get at least .01 inches on the ground to measure.

Weather Highlights

Summer High: the July high is around 84 degreesWinter Low: the January low is 40Rain: averages 21 inches of rain a yearSnow: averages 0 inches of snow a year

BESTPLACES COMFORT INDEX

The annual BestPlaces Comfort Index for Contra Costa County is 8.5 (10=best), which means it is more comfortable than most places in California.

8.5 / 10

June, September and May are the most pleasant months in Contra Costa County, while January and December are the least comfortable months.

Climate Averages

Contra Costa, California

United States

20.6 in.

38.1 in.

0.0 in.

27.8 in.

62.3 days

106.2 days

260 days

205 days

84.2°

85.8°

40.0°

21.7°

8.5

7

5.4

4.3

478 ft.

2443 ft.

CLIMATE

YOU SHOULD KNOW

Many people confuse weather and climate but they are different. Weather is the conditions of the atmosphere over a short period of time, and climate is how the atmosphere is over long periods of time.

Weather is how the atmosphere is behaving and its effects upon life and human activities. Weather can change from minute-to-minute. Most people think of weather in terms of temperature, humidity, precipitation, cloudiness, brightness, visibility, wind, and atmospheric pressure.

Climate is the description of the long-term pattern of weather in a place. Climate can mean the average weather for a particular region and time period taken over 30 years. Climate is the average of weather over time.

July is the hottest month for Contra Costa County with an average high temperature of 84.2°, which ranks it as cooler than most places in California. In Contra Costa County, there are 6 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Contra Costa County are October, June and May.

January has the coldest nighttime temperatures for Contra Costa County with an average of 40.0°. This is warmer than most places in California.

In Contra Costa County, there are 35.2 days annually when the high temperature is over 90°, which is cooler than most places in California.

In Contra Costa County, there are 8.4 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in California.

In Contra Costa County, there are 0.0 days annually when the nighttime low temperature falls below zero°, which is about average compared to other places in California.

February is the wettest month in Contra Costa County with 4.0 inches of rain, and the driest month is July with 0.0 inches. The wettest season is Spring with 57% of yearly precipitation and 0% occurs in Autumn, which is the driest season. The annual rainfall of 20.6 inches in Contra Costa County means that it is about average compared to other places in California.

January is the rainiest month in Contra Costa County with 10.9 days of rain, and July is the driest month with only 0.1 rainy days. There are 62.3 rainy days annually in Contra Costa County, which is rainier than most places in California. The rainiest season is Spring when it rains 51% of the time and the driest is Autumn with only a 2% chance of a rainy day.

There is rarely any recorded snowfall in Contra Costa County, ranking it as one of the least snowy places in California. Any measurable snowfall is a rare occurance in Contra Costa County.